Display devices have become ubiquitous in the present day. In addition to the obvious television and computer monitor implementations, display devices are present in home appliances, smart phones, billboards, stadium scoreboards, fast food restaurant menu boards, children's toys and the like. The intent usually is to deliver more content, e.g., movies, videos, pictures, graphics and the like, to users at as high of a resolution as possible.
Lighting fixtures and displays have fundamentally different requirements for consumer applications. Typically, the lighting and display functions for simultaneous capability have been separated into different fixtures.
Image displays that use liquid crystals (LC) as an element of the display usually suffer high optical losses. For example, the final light output is usually less than 10% of what was originally produced by the general illumination light emitters. This reduces the efficiency of an image display to the extent that the display's illumination efficiency cannot compare with standard luminaire efficiencies which are in the range of 100 lumens/watt. In fact, most LCD based image displays cannot perform better than 10 lumens/watt. In other words, the general illumination performance of a conventional LCD based image display does not satisfy minimal lighting requirements set by building codes or industry standards, such as Illuminating Engineering Society (IES) and American National Standards Institute (ANSI) standards. Other display technologies, such as projection displays, LED-LCD or plasma displays are optimized for the display function and offer poor illumination efficiency, and thus are similarly unsuited to general lighting. In addition, many displays usually use combinations of narrow bandwidth emitters as the sources, therefore the light output is not spectrally filled as one would expect from a typical white light luminaire. This directly relates to metrics such as CRI and R9. As a result, an image display alone is a poor substitute for a standard luminaire regardless of the type of image display (e.g., LCD, Plasma, LED or the like).